Photoresist developer and method of developing photoresist

ABSTRACT

A method of forming a pattern in a photoresist includes forming a photoresist layer over a substrate, and selectively exposing the photoresist layer to actinic radiation to form a latent pattern. The latent pattern is developed by applying a developer composition to the selectively exposed photoresist layer to form a pattern. The developer composition includes a first solvent having Hansen solubility parameters of 15&lt;δd&lt;25, 10&lt;δp&lt;25, and 6&lt;δh&lt;30; an acid having an acid dissociation constant, pKa, of −15&lt;pKa&lt;5, or a base having a pKa of 40&gt;pKa&gt;9.5; and a second solvent having a dielectric constant greater than 18. The first solvent and the second solvent are different solvents.

RELATED APPLICATION

This application claims priority to U.S. Provisional Patent ApplicationNo. 62/928,952 filed Oct. 31, 2019, the entire content of which isincorporated herein by reference.

BACKGROUND

As consumer devices have gotten smaller and smaller in response toconsumer demand, the individual components of these devices havenecessarily decreased in size as well. Semiconductor devices, which makeup a major component of devices such as mobile phones, computer tablets,and the like, have been pressured to become smaller and smaller, with acorresponding pressure on the individual devices (e.g., transistors,resistors, capacitors, etc.) within the semiconductor devices to also bereduced in size.

One enabling technology that is used in the manufacturing processes ofsemiconductor devices is the use of photolithographic materials. Suchmaterials are applied to a surface of a layer to be patterned and thenexposed to an energy that has itself been patterned. Such an exposuremodifies the chemical and physical properties of the exposed regions ofthe photosensitive material. This modification, along with the lack ofmodification in regions of the photosensitive material that were notexposed, can be exploited to remove one region without removing theother, or vice-verse.

However, as the size of individual devices has decreased, processwindows for photolithographic processing has become tighter and tighter.As such, advances in the field of photolithographic processing arenecessary to maintain the ability to scale down the devices, and furtherimprovements are needed in order to meet the desired design criteriasuch that the march towards smaller and smaller components may bemaintained.

As the semiconductor industry has progressed into nanometer technologyprocess nodes in pursuit of higher device density, higher performance,and lower costs, there have been challenges in reducing semiconductorfeature size.

BRIEF DESCRIPTION OF THE DRAWINGS

The present disclosure is best understood from the following detaileddescription when read with the accompanying figures. It is emphasizedthat, in accordance with the standard practice in the industry, variousfeatures are not drawn to scale and are used for illustration purposesonly. In fact, the dimensions of the various features may be arbitrarilyincreased or reduced for clarity of discussion.

FIG. 1 illustrates a process flow of manufacturing a semiconductordevice according to embodiments of the disclosure.

FIG. 2 shows a process stage of a sequential operation according to anembodiment of the disclosure.

FIG. 3 shows a process stage of a sequential operation according to anembodiment of the disclosure.

FIG. 4 shows a process stage of a sequential operation according to anembodiment of the disclosure.

FIG. 5 shows a process stage of a sequential operation according to anembodiment of the disclosure.

FIG. 6 shows a process stage of a sequential operation according to anembodiment of the disclosure.

FIG. 7 shows a process stage of a sequential operation according to anembodiment of the disclosure.

FIG. 8 shows a process stage of a sequential operation according to anembodiment of the disclosure.

FIG. 9 shows a process stage of a sequential operation according to anembodiment of the disclosure.

FIG. 10 shows a process stage of a sequential operation according to anembodiment of the disclosure.

FIG. 11 shows a process stage of a sequential operation according to anembodiment of the disclosure.

FIG. 12 shows a process stage of a sequential operation according to anembodiment of the disclosure.

DETAILED DESCRIPTION

It is to be understood that the following disclosure provides manydifferent embodiments, or examples, for implementing different featuresof the disclosure. Specific embodiments or examples of components andarrangements are described below to simplify the present disclosure.These are, of course, merely examples and are not intended to belimiting. For example, dimensions of elements are not limited to thedisclosed range or values, but may depend upon process conditions and/ordesired properties of the device. Moreover, the formation of a firstfeature over or on a second feature in the description that follows mayinclude embodiments in which the first and second features are formed indirect contact, and may also include embodiments in which additionalfeatures may be formed interposing the first and second features, suchthat the first and second features may not be in direct contact. Variousfeatures may be arbitrarily drawn in different scales for simplicity andclarity.

Further, spatially relative terms, such as “beneath,” “below,” “lower,”“above,” “upper” and the like, may be used herein for ease ofdescription to describe one element or feature's relationship to anotherelement(s) or feature(s) as illustrated in the figures. The spatiallyrelative terms are intended to encompass different orientations of thedevice in use or operation in addition to the orientation depicted inthe figures. The device may be otherwise oriented (rotated 90 degrees orat other orientations) and the spatially relative descriptors usedherein may likewise be interpreted accordingly. In addition, the term“made of” may mean either “comprising” or “consisting of.”

Resist scum and residue remaining in the patterned areas of thephotoresist layer after development causes increased line widthroughness and line etch roughness. The scum and residue causes defectsin photoresist patterns and results in decreased semiconductor deviceyield. Embodiments of the present disclosure address these issues, andreduce the amount of scum and residue or substantially eliminate scumand residue after development.

FIG. 1 illustrates a process flow 100 of manufacturing a semiconductordevice according to embodiments of the disclosure. A resist is coated ona surface of a layer to be patterned or a substrate 10 in operationS110, in some embodiments, to form a resist layer 15, as shown in FIG. 2. Then the resist layer 15 undergoes a first baking operation S120 toevaporate solvents in the resist composition in some embodiments. Theresist layer 15 is baked at a temperature and time sufficient to cureand dry the resist layer 15. In some embodiments, the resist layer 15 isheated at a temperature of about 40° C. and 120° C. for about 10 secondsto about 10 minutes.

After the first baking operation S120, the resist layer 15 isselectively exposed to actinic radiation 45 (see FIG. 3 ) in operationS130. In some embodiments, the resist layer 15 is selectively exposed toultraviolet radiation. In some embodiments, the ultraviolet radiation isdeep ultraviolet radiation. In some embodiments, the ultravioletradiation is extreme ultraviolet (EUV) radiation. In some embodiments,the radiation is an electron beam.

As shown in FIG. 3 , the exposure radiation 45 passes through aphotomask 30 before irradiating the resist layer 15 in some embodiments.In some embodiments, the photomask has a pattern to be replicated in theresist layer 15. The pattern is formed by an opaque pattern 35 onphotomask substrate 40, in some embodiments. The opaque pattern 35 maybe formed by a material opaque to ultraviolet radiation, such aschromium, while the photomask substrate 40 is formed of a material thatis transparent to ultraviolet radiation, such as fused quartz.

In some embodiments, the resist layer 15 is a photoresist layer. Theregion of the photoresist layer 15 exposed to radiation 52 undergoes achemical reaction thereby changing its solubility in a subsequentlyapplied developer relative to the region of the photoresist layer notexposed to radiation 50. In some embodiments, the portion of thephotoresist layer exposed to radiation 52 undergoes a crosslinkingreaction.

Next the resist layer 15 undergoes a post-exposure bake (PEB) inoperation S140. In some embodiments, the photoresist layer 15 is heatedto a temperature of about 50° C. and 250° C. for about 20 seconds toabout 300 seconds. The post-exposure baking may be used in order toassist in the generating, dispersing, and reacting of the acid/base/freeradical generated from the impingement of the radiation 45 upon theresist layer 15 during the exposure. Such assistance helps to create orenhance chemical reactions which generate chemical differences betweenthe unexposed region 50 and the exposed region 52 within the resistlayer. These chemical differences also caused differences in thesolubility between the unexposed region 50 and the exposed region 52.

The selectively exposed resist layer is subsequently developed byapplying a developer to the selectively exposed resist layer inoperation S150. As shown in FIG. 4 , a developer 57 is supplied from adispenser 62 to the resist layer 15. In some embodiments, the unexposedregion of the resist layer 50 is removed by the developer 57 forming apattern of openings 55 in the resist layer 15 to expose the substrate10, as shown in FIG. 5 .

In some embodiments, the pattern of openings 55 in the resist layer 15are extended into the layer to be patterned or substrate 10 to create apattern of openings 55′ in the substrate 10, thereby transferring thepattern in the photoresist layer 15 into the substrate 10, as shown inFIG. 6 . The pattern is extended into the substrate by etching, usingone or more suitable etchants. The exposed resist layer 15 is at leastpartially removed during the etching operation in some embodiments. Inother embodiments, the exposed resist layer 15 is removed after etchingthe substrate 10 by using a suitable photoresist stripper solvent or bya photoresist ashing operation.

In some embodiments, the substrate 10 includes a single crystallinesemiconductor layer on at least its surface portion. The substrate 10may include a single crystalline semiconductor material such as, but notlimited to Si, Ge, SiGe, GaAs, InSb, GaP, GaSb, InAlAs, InGaAs, GaSbP,GaAsSb and InP. In some embodiments, the substrate 10 is a silicon layerof an SOI (silicon-on insulator) substrate. In certain embodiments, thesubstrate 10 is made of crystalline Si.

The substrate 10 may include in its surface region, one or more bufferlayers (not shown). The buffer layers can serve to gradually change thelattice constant from that of the substrate to that of subsequentlyformed source/drain regions. The buffer layers may be formed fromepitaxially grown single crystalline semiconductor materials such as,but not limited to Si, Ge, GeSn, SiGe, GaAs, InSb, GaP, GaSb, InAlAs,InGaAs, GaSbP, GaAsSb, GaN, GaP, and InP. In an embodiment, the silicongermanium (SiGe) buffer layer is epitaxially grown on the siliconsubstrate 10. The germanium concentration of the SiGe buffer layers mayincrease from 30 atomic % for the bottom-most buffer layer to 70 atomic% for the top-most buffer layer.

In some embodiments, the substrate 10 includes at least one metal, metalalloy, and metal nitride/sulfide/oxide/silicide having the formulaMX_(a), where M is a metal and X is N, S, Se, O, Si, and a is from about0.4 to about 2.5. In some embodiments, the substrate 10 includestitanium, aluminum, cobalt, ruthenium, titanium nitride, tungstennitride, tantalum nitride, and combinations thereof.

In some embodiments, the substrate 10 includes a dielectric having atleast an oxide, or nitride of the formula MX_(b), where M is a metal orSi, X is N or O, and b ranges from about 0.4 to about 2.5. In someembodiments, the substrate 10 includes silicon dioxide, silicon nitride,aluminum oxide, hafnium oxide, lanthanum oxide, and combinationsthereof.

The photoresist layer 15 is a photosensitive layer that is patterned byexposure to actinic radiation. Typically, the chemical properties of thephotoresist regions struck by incident radiation change in a manner thatdepends on the type of photoresist used. Photoresist layers 15 arepositive tone resists or negative tone resists. A positive tone resistrefers to a photoresist material that when exposed to radiation(typically UV light) becomes soluble in a developer, while the region ofthe photoresist that is non-exposed (or exposed less) is insoluble inthe developer. A negative tone resist, on the other hand, refers to aphotoresist material that when exposed to radiation becomes insoluble inthe developer, while the region of the photoresist that is non-exposed(or exposed less) is soluble in the developer. The region of a negativetone resist that becomes insoluble upon exposure to radiation may becomeinsoluble due to a cross-linking reaction caused by the exposure toradiation.

Whether a resist is a positive tone or negative tone may depend on thetype of developer used to develop the resist. For example, some positivetone photoresists provide a positive pattern (i.e.—the exposed regionsare removed by the developer) when the developer is an aqueous-baseddeveloper, such as a tetramethylammonium hydroxide (TMAH) solution. Onthe other hand, the same photoresist provides a negative pattern(i.e.—the unexposed regions are removed by the developer) when thedeveloper is an organic solvent. Further, in some negative tonephotoresists developed with the TMAH solution, the unexposed regions ofthe photoresist are removed by the TMAH, and the exposed regions of thephotoresist, that undergo cross-linking upon exposure to actinicradiation, remain on the substrate after development. In someembodiments of the present disclosure, a negative tone photoresist isexposed to actinic radiation. The exposed portions of the negative tonephotoresist undergo crosslinking as a result of the exposure to actinicradiation, and during development the unexposed, non-crosslinkedportions of the photoresist are removed by the developer leaving theexposed regions of the photoresist remaining on the substrate.

In an embodiment, the photoresist layer 15 is a negative tonephotoresist that undergoes a cross-linking reaction upon exposure to theradiation. Photoresists according to the present disclosure include apolymer along with one or more photoactive compounds (PACs) in asolvent, in some embodiments. In some embodiments, the polymer includesa hydrocarbon structure (such as an alicyclic hydrocarbon structure)that contains one or more groups that will decompose (e.g., acid labilegroups) or otherwise react when mixed with acids, bases, or freeradicals generated by the PACs (as further described below). In someembodiments, the hydrocarbon structure includes a repeating unit thatforms a skeletal backbone of the polymer. This repeating unit mayinclude acrylic esters, methacrylic esters, crotonic esters, vinylesters, maleic diesters, fumaric diesters, itaconic diesters,(meth)acrylonitrile, (meth)acrylamides, styrenes, vinyl ethers,combinations of these, or the like.

Specific structures that are utilized for the repeating unit of thehydrocarbon structure in some embodiments, include one or more of methylacrylate, ethyl acrylate, n-propyl acrylate, isopropyl acrylate, n-butylacrylate, isobutyl acrylate, tert-butyl acrylate, n-hexyl acrylate,2-ethylhexyl acrylate, acetoxyethyl acrylate, phenyl acrylate,2-hydroxyethyl acrylate, 2-methoxyethyl acrylate, 2-ethoxyethylacrylate, 2-(2-methoxyethoxy)ethyl acrylate, cyclohexyl acrylate, benzylacrylate, 2-alkyl-2-adamantyl (meth)acrylate ordialkyl(1-adamantyl)methyl (meth)acrylate, methyl methacrylate, ethylmethacrylate, n-propyl methacrylate, isopropyl methacrylate, n-butylmethacrylate, isobutyl methacrylate, tert-butyl methacrylate, n-hexylmethacrylate, 2-ethylhexyl methacrylate, acetoxyethyl methacrylate,phenyl methacrylate, 2-hydroxyethyl methacrylate, 2-methoxyethylmethacrylate, 2-ethoxyethyl methacrylate, 2-(2-methoxyethoxy)ethylmethacrylate, cyclohexyl methacrylate, benzyl methacrylate,3-chloro-2-hydroxypropyl methacrylate, 3-acetoxy-2-hydroxypropylmethacrylate, 3-chloroacetoxy-2-hydroxypropyl methacrylate, butylcrotonate, hexyl crotonate, or the like. Examples of the vinyl estersinclude vinyl acetate, vinyl propionate, vinyl butylate, vinylmethoxyacetate, vinyl benzoate, dimethyl maleate, diethyl maleate,dibutyl maleate, dimethyl fumarate, diethyl fumarate, dibutyl fumarate,dimethyl itaconate, diethyl itaconate, dibutyl itaconate, acrylamide,methyl acrylamide, ethyl acrylamide, propyl acrylamide, n-butylacrylamide, tert-butyl acrylamide, cyclohexyl acrylamide, 2-methoxyethylacrylamide, dimethyl acrylamide, diethyl acrylamide, phenyl acrylamide,benzyl acrylamide, methacrylamide, methyl methacrylamide, ethylmethacrylamide, propyl methacrylamide, n-butyl methacrylamide,tert-butyl methacrylamide, cyclohexyl methacrylamide, 2-methoxyethylmethacrylamide, dimethyl methacrylamide, diethyl methacrylamide, phenylmethacrylamide, benzyl methacrylamide, methyl vinyl ether, butyl vinylether, hexyl vinyl ether, methoxyethyl vinyl ether, dimethylaminoethylvinyl ether, or the like. Examples of styrenes include styrene, methylstyrene, dimethyl styrene, trimethyl styrene, ethyl styrene, isopropylstyrene, butyl styrene, methoxy styrene, butoxy styrene, acetoxystyrene, chloro styrene, dichloro styrene, bromo styrene, vinyl methylbenzoate, α-methyl styrene, maleimide, vinylpyridine, vinylpyrrolidone,vinylcarbazole, combinations of these, or the like.

In some embodiments, the repeating unit of the hydrocarbon structurealso has either a monocyclic or a polycyclic hydrocarbon structuresubstituted into it, or the monocyclic or polycyclic hydrocarbonstructure is the repeating unit, in order to form an alicyclichydrocarbon structure. Specific examples of monocyclic structures insome embodiments include bicycloalkane, tricycloalkane,tetracycloalkane, cyclopentane, cyclohexane, or the like. Specificexamples of polycyclic structures in some embodiments includeadamantane, norbornane, isobornane, tricyclodecane, tetracyclododecane,or the like.

The group which will decompose, otherwise known as a leaving group or,in some embodiments in which the PAC is a photoacid generator, an acidlabile group, is attached to the hydrocarbon structure so that it willreact with the acids/bases/free radicals generated by the PACs duringexposure. In some embodiments, the group which will decompose is acarboxylic acid group, a fluorinated alcohol group, a phenolic alcoholgroup, a sulfonic group, a sulfonamide group, a sulfonylimido group, an(alkylsulfonyl) (alkylcarbonyl)methylene group, an(alkylsulfonyl)(alkyl-carbonyl)imido group, abis(alkylcarbonyl)methylene group, a bis(alkylcarbonyl)imido group, abis(alkylsulfonyl)methylene group, a bis(alkylsulfonyl)imido group, atris(alkylcarbonyl methylene group, a tris(alkylsulfonyl)methylenegroup, combinations of these, or the like. Specific groups that are usedfor the fluorinated alcohol group include fluorinated hydroxyalkylgroups, such as a hexafluoroisopropanol group in some embodiments.Specific groups that are used for the carboxylic acid group includeacrylic acid groups, methacrylic acid groups, or the like.

In some embodiments, the polymer also includes other groups attached tothe hydrocarbon structure that help improve a variety of properties ofthe polymerizable resin. For example, inclusion of a lactone group tothe hydrocarbon structure assists to reduce the amount of line edgeroughness after the photoresist has been developed, thereby helpingreduce the number of defects that occur during development. In someembodiments, the lactone groups include rings having five to sevenmembers, although any suitable lactone structure may alternatively beused for the lactone group.

In some embodiments, the polymer includes groups that can assist inincreasing the adhesiveness of the photoresist layer 15 to underlyingstructures (e.g., substrate 10). Polar groups may be used to helpincrease the adhesiveness. Suitable polar groups include hydroxylgroups, cyano groups, or the like, although any suitable polar groupmay, alternatively, be used.

Optionally, the polymer includes one or more alicyclic hydrocarbonstructures that do not also contain a group which will decompose in someembodiments. In some embodiments, the hydrocarbon structure that doesnot contain a group which will decompose includes structures such as1-adamantyl(meth)acrylate, tricyclodecanyl (meth)acrylate, cyclohexayl(methacrylate), combinations of these, or the like.

Additionally, some embodiments of the photoresist include one or morephotoactive compounds (PACs). The PACs are photoactive components, suchas photoacid generators, photobase generators, free-radical generators,or the like. The PACs may be positive-acting or negative-acting. In someembodiments in which the PACs are a photoacid generator, the PACsinclude halogenated triazines, onium salts, diazonium salts, aromaticdiazonium salts, phosphonium salts, sulfonium salts, iodonium salts,imide sulfonate, oxime sulfonate, diazodisulfone, disulfone,o-nitrobenzylsulfonate, sulfonated esters, halogenated sulfonyloxydicarboximides, diazodisulfones, α-cyanooxyamine-sulfonates,imidesulfonates, ketodiazosulfones, sulfonyldiazoesters,1,2-di(arylsulfonyl)hydrazines, nitrobenzyl esters, and the s-triazinederivatives, combinations of these, or the like.

Alternatively, in some embodiments in which the coupling reagent isadded to the photoresist without the cross-linking agent, the couplingreagent is used to couple one group from one of the hydrocarbonstructures in the polymer to a second group from a separate one of thehydrocarbon structures in order to cross-link and bond the two polymerstogether. However, in such an embodiment the coupling reagent, unlikethe cross-linking agent, does not remain as part of the polymer, andonly assists in bonding one hydrocarbon structure directly to anotherhydrocarbon structure.

In some embodiments in which the PACs are free-radical generators, thePACs include n-phenylglycine; aromatic ketones, including benzophenone,N,N′-tetramethyl-4,4′-diaminobenzophenone,N,N′-tetraethyl-4,4′-diaminobenzophenone,4-methoxy-4′-dimethylaminobenzo-phenone,3,3′-dimethyl-4-methoxybenzophenone,p,p′-bis(dimethylamino)benzo-phenone,p,p′-bis(diethylamino)-benzophenone; anthraquinone,2-ethylanthraquinone; naphthaquinone; and phenanthraquinone; benzoinsincluding benzoin, benzoinmethylether, benzoinisopropylether,benzoin-n-butylether, benzoin-phenylether, methylbenzoin andethylbenzoin; benzyl derivatives, including dibenzyl,benzyldiphenyldisulfide, and benzyldimethylketal; acridine derivatives,including 9-phenylacridine, and 1,7-bis(9-acridinyl)heptane;thioxanthones, including 2-chlorothioxanthone, 2-methylthioxanthone,2,4-diethylthioxanthone, 2,4-dimethylthioxanthone, and2-isopropylthioxanthone; acetophenones, including1,1-dichloroacetophenone, p-t-butyldichloro-acetophenone,2,2-diethoxyacetophenone, 2,2-dimethoxy-2-phenylacetophenone, and2,2-dichloro-4-phenoxyacetophenone; 2,4,5-triarylimidazole dimers,including 2-(o-chlorophenyl)-4,5-diphenylimidazole dimer,2-(o-chlorophenyl)-4,5-di-(m-methoxyphenyl imidazole dimer,2-(o-fluorophenyl)-4,5-diphenylimidazole dimer,2-(o-methoxyphenyl)-4,5-diphenylimidazole dimer,2-(p-methoxyphenyl)-4,5-diphenylimidazole dimer,2,4-di(p-methoxyphenyl)-5-phenylimidazole dimer,2-(2,4-dimethoxyphenyl)-4,5-diphenylimidazole dimer and2-(p-methylmercaptophenyl)-4,5-diphenylimidazole dimmer; combinations ofthese, or the like.

In some embodiments in which the PACs are photobase generators, the PACsincludes quaternary ammonium dithiocarbamates, a aminoketones,oxime-urethane containing molecules such as dibenzophenoneoximehexamethylene diurethan, ammonium tetraorganylborate salts, andN-(2-nitrobenzyloxycarbonyl)cyclic amines, combinations of these, or thelike.

As one of ordinary skill in the art will recognize, the chemicalcompounds listed herein are merely intended as illustrated examples ofthe PACs and are not intended to limit the embodiments to only thosePACs specifically described. Rather, any suitable PAC may be used, andall such PACs are fully intended to be included within the scope of thepresent embodiments.

In some embodiments, a cross-linking agent is added to the photoresist.The cross-linking agent reacts with one group from one of thehydrocarbon structures in the polymer and also reacts with a secondgroup from a separate one of the hydrocarbon structures in order tocross-link and bond the two hydrocarbon structures together. Thisbonding and cross-linking increases the molecular weight of the polymerproducts of the cross-linking reaction and increases the overall linkingdensity of the photoresist. Such an increase in density and linkingdensity helps to improve the resist pattern.

In some embodiments the cross-linking agent has the following structure:

wherein C is carbon, n ranges from 1 to 15; A and B independentlyinclude a hydrogen atom, a hydroxyl group, a halide, an aromatic carbonring, or a straight or cyclic alkyl, alkoxyl/fluoro, alkyl/fluoroalkoxylchain having a carbon number of between 1 and 12, and each carbon Ccontains A and B; a first terminal carbon C at a first end of a carbon Cchain includes X and a second terminal carbon C at a second end of thecarbon chain includes Y, wherein X and Y independently include an aminegroup, a thiol group, a hydroxyl group, an isopropyl alcohol group, oran isopropyl amine group, except when n=1 then X and Y are bonded to thesame carbon C. Specific examples of materials that may be used as thecross-linking agent include the following:

Alternatively, instead of or in addition to the cross-linking agentbeing added to the photoresist composition, a coupling reagent is addedin some embodiments, in which the coupling reagent is added in additionto the cross-linking agent. The coupling reagent assists thecross-linking reaction by reacting with the groups on the hydrocarbonstructure in the polymer before the cross-linking reagent, allowing fora reduction in the reaction energy of the cross-linking reaction and anincrease in the rate of reaction. The bonded coupling reagent thenreacts with the cross-linking agent, thereby coupling the cross-linkingagent to the polymer.

Alternatively, in some embodiments in which the coupling reagent isadded to the photoresist 12 without the cross-linking agent, thecoupling reagent is used to couple one group from one of the hydrocarbonstructures in the polymer to a second group from a separate one of thehydrocarbon structures in order to cross-link and bond the two polymerstogether. However, in such an embodiment the coupling reagent, unlikethe cross-linking agent, does not remain as part of the polymer, andonly assists in bonding one hydrocarbon structure directly to anotherhydrocarbon structure.

In some embodiments, the coupling reagent has the following structure:

where R is a carbon atom, a nitrogen atom, a sulfur atom, or an oxygenatom; M includes a chlorine atom, a bromine atom, an iodine atom, —NO₂;—SO₃—; —H—; —CN; —NCO, —OCN; —CO₂—; —OH; —OR*, —OC(O)CR*; —SR,—SO₂N(R*)₂; —SO₂R*; SOR; —OC(O)R*; —C(O)OR*; —C(O)R*; —Si(OR*)₃;—Si(R*)₃; epoxy groups, or the like; and R* is a substituted orunsubstituted C1-C12 alkyl, C1-C12 aryl, C1-C12 aralkyl, or the like.Specific examples of materials used as the coupling reagent in someembodiments include the following:

The individual components of the photoresist are placed into a solventin order to aid in the mixing and dispensing of the photoresist. To aidin the mixing and dispensing of the photoresist, the solvent is chosenat least in part based upon the materials chosen for the polymer as wellas the PACs. In some embodiments, the solvent is chosen such that thepolymer and the PACs can be evenly dissolved into the solvent anddispensed upon the layer to be patterned.

In some embodiments, the photoresist solvent is an organic solvent, andincludes any suitable solvent such as ketones, alcohols, polyalcohols,ethers, glycol ethers, cyclic ethers, aromatic hydrocarbons, esters,propionates, lactates, lactic esters, alkylene glycol monoalkyl ethers,alkyl lactates, alkyl alkoxypropionates, cyclic lactones, monoketonecompounds that contain a ring, alkylene carbonates, alkyl alkoxyacetate,alkyl pyruvates, lactate esters, ethylene glycol alkyl ether acetates,diethylene glycols, propylene glycol alkyl ether acetates, alkyleneglycol alkyl ether esters, alkylene glycol monoalkyl esters, or thelike.

Specific examples of materials that may be used as the solvent for thephotoresist include, acetone, methanol, ethanol, toluene, xylene,4-hydroxy-4-methyl-2-pentatone, tetrahydrofuran, methyl ethyl ketone,cyclohexanone, methyl isoamyl ketone, 2-heptanone, ethylene glycol,ethylene glycol monoacetate, ethylene glycol dimethyl ether, ethyleneglycol dimethyl ether, ethylene glycol methylethyl ether, ethyleneglycol monoethyl ether, methyl cellosolve acetate, ethyl cellosolveacetate, diethylene glycol, diethylene glycol monoacetate, diethyleneglycol monomethyl ether, diethylene glycol diethyl ether, diethyleneglycol dimethyl ether, diethylene glycol ethylmethyl ether,diethethylene glycol monoethyl ether, diethylene glycol monobutyl ether,ethyl 2-hydroxypropionate, methyl 2-hydroxy-2-methylpropionate, ethyl2-hydroxy-2-methylpropionate, ethyl ethoxyacetate, ethyl hydroxyacetate,methyl 2-hydroxy-2-methylbutanate, methyl 3-methoxypropionate, ethyl3-methoxypropionate, methyl 3-ethoxypropionate, ethyl3-ethoxypropionate, methyl acetate, ethyl acetate, propyl acetate, butylacetate, methyl lactate, ethyl lactate, propyl lactate, butyl lactate,propylene glycol, propylene glycol monoacetate, propylene glycolmonoethyl ether acetate, propylene glycol monomethyl ether acetate,propylene glycol monopropyl methyl ether acetate, propylene glycolmonobutyl ether acetate, propylene glycol monobutyl ether acetate,propylene glycol monomethyl ether propionate, propylene glycol monoethylether propionate, propylene glycol methyl ether acetate, propyleneglycol ethyl ether acetate, ethylene glycol monomethyl ether acetate,ethylene glycol monoethyl ether acetate, propylene glycol monomethylether, propylene glycol monoethyl ether, propylene glycol monopropylether, propylene glycol monobutyl ether, ethylene glycol monomethylether, ethylene glycol monoethyl ether, ethyl 3-ethoxypropionate, methyl3-methoxypropionate, methyl 3-ethoxypropionate, and ethyl3-methoxypropionate, β-propiolactone, β-butyrolactone, γ-butyrolactone,α-methyl-γ-butyrolactone, β-methyl-γ-butyrolactone, γ-valerolactone,γ-caprolactone, γ-octanoic lactone, α-hydroxy-γ-butyrolactone,2-butanone, 3-methylbutanone, pinacolone, 2-pentanone, 3-pentanone,4-methyl-2-pentanone, 2-methyl-3-pentanone, 4,4-dimethyl-2-pentanone,2,4-dimethyl-3-pentanone, 2,2,4,4-tetramethyl-3-pentanone, 2-hexanone,3-hexanone, 5-methyl-3-hexanone, 2-heptanone, 3-heptanone, 4-heptanone,2-methyl-3-heptanone, 5-methyl-3-heptanone, 2,6-dimethyl-4-heptanone,2-octanone, 3-octanone, 2-nonanone, 3-nonanone, 5-nonanone, 2-decanone,3-decanone, 4-decanone, 5-hexene-2-one, 3-pentene-2-one, cyclopentanone,2-methylcyclopentanone, 3-methylcyclopentanone,2,2-dimethylcyclopentanone, 2,4,4-trimethylcyclopentanone,cyclohexanone, 3-methylcyclohexanone, 4-methylcyclohexanone,4-ethylcyclohexanone, 2,2-dimethylcyclohexanone,2,6-dimethylcyclohexanone, 2,2,6-trimethylcyclohexanone, cycloheptanone,2-methylcycloheptanone, 3-methylcycloheptanone, propylene carbonate,vinylene carbonate, ethylene carbonate, butylene carbonate,acetate-2-methoxyethyl, acetate-2-ethoxyethyl,acetate-2-(2-ethoxyethoxy)ethyl, acetate-3-methoxy-3-methylbutyl,acetate-1-methoxy-2-propyl, dipropylene glycol, monomethylether,monoethylether, monopropylether, monobutylether, monophenylether,dipropylene glycol monoacetate, dioxane, methyl pyruvate, ethylpyruvate, propyl pyruvate, methyl methoxypropionate, ethylethoxypropionate, n-methylpyrrolidone (NMP), 2-methoxyethyl ether(diglyme), ethylene glycol monomethyl ether, propylene glycol monomethylether, methyl propionate, ethyl propionate, ethyl ethoxy propionate,methylethyl ketone, cyclohexanone, 2-heptanone, cyclopentanone,cyclohexanone, ethyl 3-ethoxypropionate, propylene glycol methyl etheracetate (PGMEA), methylene cellosolve, 2-ethoxyethanol,N-methylformamide, N,N-dimethylformamide, N-methylformanilide,N-methylacetamide, N,N-dimethylacetamide, dimethylsulfoxide, benzylethyl ether, dihexyl ether, acetonylacetone, isophorone, caproic acid,caprylic acid, 1-octanol, 1-nonanol, benzyl alcohol, benzyl acetate,ethyl benzoate, diethyl oxalate, diethyl maleate, phenyl cellosolveacetate, or the like.

As one of ordinary skill in the art will recognize, the materials listedand described above as examples of materials that may be used for thesolvent component of the photoresist are merely illustrative and are notintended to limit the embodiments. Rather, any suitable material thatdissolves the polymer and the PACs may be used to help mix and apply thephotoresist. All such materials are fully intended to be included withinthe scope of the embodiments.

Additionally, while individual ones of the above described materials maybe used as the solvent for the photoresist, in other embodiments morethan one of the above described materials are used. For example, in someembodiments, the solvent includes a combination mixture of two or moreof the materials described. All such combinations are fully intended tobe included within the scope of the embodiments.

In addition to the polymers, the PACs, the solvents, the cross-linkingagent, and the coupling reagent, some embodiments of the photoresistalso include a number of other additives that assist the photoresist toobtain high resolution. For example, some embodiments of the photoresistalso includes surfactants in order to help improve the ability of thephotoresist to coat the surface on which it is applied. In someembodiments, the surfactants include nonionic surfactants, polymershaving fluorinated aliphatic groups, surfactants that contain at leastone fluorine atom and/or at least one silicon atom, polyoxyethylenealkyl ethers, polyoxyethylene alkyl aryl ethers,polyoxyethylene-polyoxypropylene block copolymers, sorbitan fatty acidesters, and polyoxyethylene sorbitan fatty acid esters.

Specific examples of materials used as surfactants in the photoresistcomposition in some embodiments include polyoxyethylene lauryl ether,polyoxyethylene stearyl ether, polyoxyethylene cetyl ether,polyoxyethylene oleyl ether, polyoxyethylene octyl phenol ether,polyoxyethylene nonyl phenol ether, sorbitan monolaurate, sorbitanmonopalmitate, sorbitan monostearate, sorbitan monooleate, sorbitantrioleate, sorbitan tristearate, polyoxyethylene sorbitan monolaurate,polyoxyethylene sorbitan monopalmitate, polyoxyethylene sorbitanmonostearate, polyoxyethylene sorbitan trioleate, polyoxyethylenesorbitan tristearate, polyethylene glycol distearate, polyethyleneglycol dilaurate, polyethylene glycol dilaurate, polyethylene glycol,polypropylene glycol, polyoxyethylenestearyl ether, polyoxyethylenecetyl ether, fluorine containing cationic surfactants, fluorinecontaining nonionic surfactants, fluorine containing anionicsurfactants, cationic surfactants and anionic surfactants, polyethyleneglycol, polypropylene glycol, polyoxyethylene cetyl ether, combinationsthereof, or the like.

Another additive added to some embodiments of the photoresist is aquencher, which inhibits diffusion of the generated acids/bases/freeradicals within the photoresist. The quencher improves the resistpattern configuration as well as the stability of the photoresist overtime. In an embodiment, the quencher is an amine, such as a second loweraliphatic amine, a tertiary lower aliphatic amine, or the like. Specificexamples of amines include trimethylamine, diethylamine, triethylamine,di-n-propylamine, tri-n-propylamine, tripentylamine, diethanolamine, andtriethanolamine, alkanolamine, combinations thereof, or the like.

In some embodiments, an organic acid is used as the quencher. Specificembodiments of organic acids include malonic acid, citric acid, malicacid, succinic acid, benzoic acid, salicylic acid; phosphorous oxo acidand its derivatives, such as phosphoric acid and derivatives thereofsuch as its esters, phosphoric acid di-n-butyl ester and phosphoric aciddiphenyl ester; phosphonic acid and derivatives thereof such as itsester, such as phosphonic acid dimethyl ester, phosphonic aciddi-n-butyl ester, phenylphosphonic acid, phosphonic acid diphenyl ester,and phosphonic acid dibenzyl ester; and phosphinic acid and derivativesthereof such as its esters, including phenylphosphinic acid.

Another additive added to some embodiments of the photoresist is astabilizer, which assists in preventing undesired diffusion of the acidsgenerated during exposure of the photoresist. In some embodiments, thestabilizer includes nitrogenous compounds, including aliphatic primary,secondary, and tertiary amines; cyclic amines, including piperidines,pyrrolidines, morpholines; aromatic heterocycles, including pyridines,pyrimidines, purines; imines, including diazabicycloundecene,guanidines, imides, amides, or the like. Alternatively, ammonium saltsare also be used for the stabilizer in some embodiments, including,primary, secondary, tertiary, and quaternary alkyl- and aryl-ammoniumsalts of alkoxides, including hydroxide, phenolates, carboxylates, aryland alkyl sulfonates, sulfonamides, or the like. Other cationicnitrogenous compounds, including pyridinium salts and salts of otherheterocyclic nitrogenous compounds with anions, such as alkoxides,including hydroxide, phenolates, carboxylates, aryl and alkylsulfonates, sulfonamides, or the like, are used in some embodiments.

Another additive in some embodiments of the photoresist is a dissolutioninhibitor to help control dissolution of the photoresist duringdevelopment. In an embodiment bile-salt esters may be utilized as thedissolution inhibitor. Specific examples of dissolution inhibitors insome embodiments include cholic acid, deoxycholic acid, lithocholicacid, t-butyl deoxycholate, t-butyl lithocholate, and t-butyl-3-acetyllithocholate.

Another additive in some embodiments of the photoresist is aplasticizer. Plasticizers may be used to reduce delamination andcracking between the photoresist and underlying layers (e.g., the layerto be patterned). Plasticizers include monomeric, oligomeric, andpolymeric plasticizers, such as oligo- and polyethyleneglycol ethers,cycloaliphatic esters, and non-acid reactive steroidaly-derivedmaterials. Specific examples of materials used for the plasticizer insome embodiments include dioctyl phthalate, didodecyl phthalate,triethylene glycol dicaprylate, dimethyl glycol phthalate, tricresylphosphate, dioctyl adipate, dibutyl sebacate, triacetyl glycerine, orthe like.

A coloring agent is another additive included in some embodiments of thephotoresist. The coloring agent aids observers in examining and findingany defects that may need to be remedied prior to further processing. Insome embodiments, the coloring agent is a triarylmethane dye or a fineparticle organic pigment. Specific examples of materials in someembodiments include crystal violet, methyl violet, ethyl violet, oilblue #603, Victoria Pure Blue BOH, malachite green, diamond green,phthalocyanine pigments, azo pigments, carbon black, titanium oxide,brilliant green dye (C. I. 42020), Victoria Pure Blue FGA (Linebrow),Victoria BO (Linebrow) (C. I. 42595), Victoria Blue BO (C. I. 44045),rhodamine 6G (C. I. 45160), benzophenone compounds, such as2,4-dihydroxybenzophenone and 2,2′,4,4′-tetrahydroxybenzophenone;salicylic acid compounds, such as phenyl salicylate and 4-t-butylphenylsalicylate; phenylacrylate compounds, such asethyl-2-cyano-3,3-diphenylacrylate, and2′-ethylhexyl-2-cyano-3,3-diphenylacrylate; benzotriazole compounds,such as 2-(2-hydroxy-5-methylphenyl)-2H-benzotriazole, and2-(3-t-butyl-2-hydroxy-5-methylphenyl)-5-chloro-2H-benzotriazole;coumarin compounds, such as 4-methyl-7-diethylamino-1-benzopyran-2-one;thioxanthone compounds, such as diethylthioxanthone; stilbene compounds,naphthalic acid compounds, azo dyes, phthalocyanine blue, phthalocyaninegreen, iodine green, Victoria blue, crystal violet, titanium oxide,naphthalene black, Photopia methyl violet, bromphenol blue andbromcresol green; laser dyes, such as Rhodamine G6, Coumarin 500, DCM(4-(dicyanomethylene)-2-methyl-6-(4-dimethylaminostyryl)-4H pyran)),Kiton Red 620, Pyrromethene 580, or the like. Additionally, one or morecoloring agents may be used in combination to provide the desiredcoloring.

Adhesion additives are added to some embodiments of the photoresist topromote adhesion between the photoresist and an underlying layer uponwhich the photoresist has been applied (e.g., the layer to bepatterned). In some embodiments, the adhesion additives include a silanecompound with at least one reactive substituent such as a carboxylgroup, a methacryloyl group, an isocyanate group and/or an epoxy group.Specific examples of the adhesion components include trimethoxysilylbenzoic acid, γ-methacryloxypropyl trimethoxy silane,vinyltriacetoxysilane, vinyltrimethoxysilane, γ-isocyanatepropyltriethoxy silane, γ-glycidoxypropyl trimethoxy silane,β-(3,4-epoxycyclohexyl)ethyl trimethoxy silane, benzimidazoles andpolybenzimidazoles, a lower hydroxyalkyl substituted pyridinederivative, a nitrogen heterocyclic compound, urea, thiourea, anorganophosphorus compound, 8-oxyquinoline, 4-hydroxypteridine andderivatives, 1,10-phenanthroline and derivatives, 2,2′-bipyridine andderivatives, benzotriazoles, organophosphorus compounds,phenylenediamine compounds, 2-amino-1-phenylethanol,N-phenylethanolamine, N-ethyldiethanolamine, N-ethylethanolamine andderivatives, benzothiazole, and a benzothiazoleamine salt having acyclohexyl ring and a morpholine ring,3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropyltriethoxysilane,3-mercaptopropyltrimethoxysilane, 3-mercaptopropyltriethoxysilane,3-methacryloyloxypropyltrimethoxysilane, vinyl trimethoxysilane,combinations thereof, or the like.

Metal oxide nanoparticles are added to some embodiments of thephotoresist. In some embodiments, the photoresist includes one or moremetal oxides nanoparticles selected from the group consisting oftitanium dioxide, zinc oxide, zirconium dioxide, nickel oxide, cobaltoxide, manganese oxide, copper oxides, iron oxides, strontium titanate,tungsten oxides, vanadium oxides, chromium oxides, tin oxides, hafniumoxide, indium oxide, cadmium oxide, molybdenum oxide, tantalum oxides,niobium oxide, aluminum oxide, and combinations thereof. As used herein,nanoparticles are particles having an average particle diameter between1 and 100 nm.

Surface leveling agents are added to some embodiments of the photoresistto assist a top surface of the photoresist to be level, so thatimpinging light will not be adversely modified by an unlevel surface. Insome embodiments, surface leveling agents include fluoroaliphaticesters, hydroxyl terminated fluorinated polyethers, fluorinated ethyleneglycol polymers, silicones, acrylic polymer leveling agents,combinations thereof, or the like.

In some embodiments, the polymer and the PACs, along with any desiredadditives or other agents, are added to the solvent for application.Once added, the mixture is then mixed in order to achieve a homogenouscomposition throughout the photoresist to ensure that there are nodefects caused by uneven mixing or nonhomogenous composition of thephotoresist. Once mixed together, the photoresist may either be storedprior to its usage or used immediately.

Once ready, the photoresist is applied onto the layer to be patterned,as shown in FIG. 2 , such as the substrate 10 to form a photoresistlayer 15. In some embodiments, the photoresist is applied using aprocess such as a spin-on coating process, a dip coating method, anair-knife coating method, a curtain coating method, a wire-bar coatingmethod, a gravure coating method, a lamination method, an extrusioncoating method, combinations of these, or the like. In some embodiments,the photoresist layer 15 thickness ranges from about 10 nm to about 300nm.

After the photoresist layer 15 has been applied to the substrate 10, apre-exposure bake of the photoresist layer is performed in someembodiments to cure and dry the photoresist prior to radiation exposure(see FIG. 1 ). The curing and drying of the photoresist layer 15 removesthe solvent component while leaving behind the polymer, the PACs, thecross-linking agent, and the other chosen additives. In someembodiments, the pre-exposure baking is performed at a temperaturesuitable to evaporate the solvent, such as between about 50° C. and 250°C., although the precise temperature depends upon the materials chosenfor the photoresist. The pre-baking is performed for a time sufficientto cure and dry the photoresist layer, such as between about 10 secondsto about 10 minutes.

FIG. 3 illustrates a selective exposure of the photoresist layer to forman exposed region 52 and an unexposed region 50. In some embodiments,the exposure to radiation is carried out by placing the photoresistcoated substrate in a photolithography tool. The photolithography toolincludes a photomask 30, optics, an exposure radiation source to providethe radiation 45 for exposure, and a movable stage for supporting andmoving the substrate under the exposure radiation.

In some embodiments, the radiation source (not shown) supplies radiation45, such as ultraviolet light, to the photoresist layer 15 in order toinduce a reaction of the PACs, which in turn reacts with the polymer tochemically alter those regions of the photoresist layer to which theradiation 45 impinges. In some embodiments, the radiation iselectromagnetic radiation, such as g-line (wavelength of about 436 nm),i-line (wavelength of about 365 nm), ultraviolet radiation, farultraviolet radiation, extreme ultraviolet, electron beams, or the like.In some embodiments, the radiation source is selected from the groupconsisting of a mercury vapor lamp, xenon lamp, carbon arc lamp, a KrFexcimer laser light (wavelength of 248 nm), an ArF excimer laser light(wavelength of 193 nm), an F₂ excimer laser light (wavelength of 157nm), or a CO₂ laser-excited Sn plasma (extreme ultraviolet, wavelengthof 13.5 nm).

In some embodiments, optics (not shown) are used in the photolithographytool to expand, reflect, or otherwise control the radiation before orafter the radiation 45 is patterned by the photomask 30. In someembodiments, the optics include one or more lenses, mirrors, filters,and combinations thereof to control the radiation 45 along its path.

In an embodiment, the patterned radiation 45 is extreme ultravioletlight having a 13.5 nm wavelength, the PAC is a photoacid generator, thegroup to be decomposed is a carboxylic acid group on the hydrocarbonstructure, and a cross linking agent is used. The patterned radiation 45impinges upon the photoacid generator, the photoacid generator absorbsthe impinging patterned radiation 45. This absorption initiates thephotoacid generator to generate a proton (e.g., a H⁺ atom) within thephotoresist layer 15. When the proton impacts the carboxylic acid groupon the hydrocarbon structure, the proton reacts with the carboxylic acidgroup, chemically altering the carboxylic acid group and altering theproperties of the polymer in general. The carboxylic acid group thenreacts with the cross-linking agent to cross-link with other polymerswithin the exposed region of the photoresist layer 15.

In some embodiments, the exposure of the photoresist layer 15 uses animmersion lithography technique. In such a technique, an immersionmedium (not shown) is placed between the final optics and thephotoresist layer, and the exposure radiation 45 passes through theimmersion medium.

After the photoresist layer 15 has been exposed to the exposureradiation 45, a post-exposure baking is performed in some embodiments toassist in the generating, dispersing, and reacting of the acid/base/freeradical generated from the impingement of the radiation 45 upon the PACsduring the exposure. Such thermal assistance helps to create or enhancechemical reactions, which generate chemical differences between theexposed region 52 and the unexposed region 5 within the photoresistlayer 15. These chemical differences also cause differences in thesolubility between the exposed region 52 and the unexposed region 50. Insome embodiments, the post-exposure baking occurs at temperaturesranging from about 50° C. to about 250° C. for a period of between about20 seconds and about 300 seconds.

The inclusion of the cross-linking agent into the chemical reactionshelps the components of the polymer (e.g., the individual polymers)react and bond with each other, increasing the molecular weight of thebonded polymer in some embodiments. In particular, an initial polymerhas a side chain with a carboxylic acid protected by one of the groupsto be removed/acid labile groups. The groups to be removed are removedin a de-protecting reaction, which is initiated by a proton H⁺ generatedby, e.g., the photoacid generator during either the exposure process orduring the post-exposure baking process. The H⁺ first removes the groupsto be removed/acid labile groups and another hydrogen atom may replacethe removed structure to form a de-protected polymer. Once de-protected,a cross-linking reaction occurs between two separate de-protectedpolymers that have undergone the de-protecting reaction and thecross-linking agent in a cross-linking reaction. In particular, hydrogenatoms within the carboxylic groups formed by the de-protecting reactionare removed and the oxygen atoms react with and bond with thecross-linking agent. This bonding of the cross-linking agent to twopolymers bonds the two polymers not only to the cross-linking agent butalso bonds the two polymers to each other through the cross-linkingagent, thereby forming a cross-linked polymer.

By increasing the molecular weight of the polymers through thecross-linking reaction, the new cross-linked polymer becomes lesssoluble in negative tone resist developers.

In some embodiments, the photoresist developer composition 57 includes afirst solvent, an acid or a base, and second solvent having a dielectricconstant greater than 18. The first solvent and the second solvent aredifferent solvents in some embodiments. In some embodiments, theconcentration of the first solvent is from about 60 wt. % to about 99wt. % based on the total weight of the photoresist developercomposition. The acid or base concentration is from about 0.001 wt. % toabout 20 wt. % based on the total weight of the photoresist developercomposition. In certain embodiments, the acid or base concentration inthe developer is from about 0.01 wt. % to about 15 wt. % based on thetotal weight of the photoresist developer composition. In certainembodiments, the second solvent concentration in the developer is fromabout 1 wt. % to about 40 wt. % based on the total weight of thephotoresist developer composition. At concentrations of the solventcomponents outsided the disclosed ranges, developer compositionperformance and development efficiency may be reduced, leading toincreased photoresist residue and scum in the photoresist pattern, andincreased line width roughness and line edge roughness.

In some embodiments, the first solvent has Hansen solubility parametersof 15<δ_(d)<25, 10<δ_(p)<25, and 6<δ_(h)<30. The units of the Hansensolubility parameters are (Joules/cm³)^(1/2) or, equivalently, MPa^(1/2)and are based on the idea that one molecule is defined as being likeanother if it bonds to itself in a similar way. δ_(d) is the energy fromdispersion forces between molecules. δ_(p) is the energy from dipolarintermolecular force between the molecules. δ_(h) is the energy fromhydrogen bonds between molecules. The three parameters, δ_(d), δ_(p),and δ_(h), can be considered as coordinates for a point in threedimensions, known as the Hansen space. The nearer two molecules are inHansen space, the more likely they are to dissolve into each other.

First solvents having the desired Hansen solubility parameters includehexane, benzene, dimethyl sulfoxide, acetone, ethylene glycol, methanol,ethanol, propanol, isopropanol, propanediol, 4-methyl-2-pentanone,butyldiglycol, ethyl acetate, butyl acetate, propylene glycol methylether acetate, propylene glycol methyl ether, diethyl ether, isobutylpropionate, tetrahydrofuran, hydrogen peroxide, or water.

In some embodiments, the acid has an acid dissociation constant, pK_(a),of −15<pK_(a)<5. In some embodiments, the base has a pK_(a) of40>pK_(a)>9.5. The acid dissociation constant, pK_(a), is thelogarithmic constant of the acid dissociation constant K_(a). K_(a) is aquantitative measure of the strength of an acid in solution. K_(a) isthe equilibrium constant for the dissociation of a generic acidaccording to the equation HA+H₂O↔A⁻+H₃O⁺, where HA dissociates into itsconjugate base, A⁻, and a hydrogen ion which combines with a watermolecule to form a hydronium ion. The dissociation constant can beexpressed as a ratio of the equilibrium concentrations:

$K_{a} = {\frac{\lbrack A^{-} \rbrack\lbrack {H_{3}O^{+}} \rbrack}{{\lbrack{HA}\rbrack\;\lbrack {H_{2}O} \rbrack}\;}.}$In most cases, the amount of water is constant and the equation can besimplified to

HA ↔ A⁻ + H⁺, and$K_{a} = {\frac{\lbrack A^{-} \rbrack\lbrack H^{+} \rbrack}{\lbrack{HA}\rbrack}.}$The logarithmic constant, pK_(a) is related to K_(a) by the equationpK_(a)=−log₁₀(K_(a)). The lower the value of pK_(a) the stronger theacid. Conversely, the higher the value of pK_(a) the stronger the base.

In some embodiments, suitable acids for the photoresist developercomposition 57 include an organic acid selected from the groupconsisting of formic acid, acetic acid, ethanedioic acid,2-hydroxyethanoic acid, oxoethanoic acid, propanoic acid, propanedioicacid, 2-hydroxypropanoic acid, butanoic acid, 2-hydroxybutanedioic acid,butanedioic acid, 3-oxobutanoic acid, pentanoic acid, hexanoic acid,heptanoic acid, caprylic acid, citric acid, uric acid,trifluoromethanesulfonic acid, benzenesulfonic acid, ethanesulfonicacid, methanesulfonic acid, oxalic acid, maleic acid, carbonic acid,hydroxylamine-o-sulfonic acid, formamidinesulfinic acid, methylsulfamicacid, sulfoacetic acid, 1,1,2,2-tetrafluoroethanesulfonic acid,1,3-propanedisulfonic acid, nonafluorobutane-1-sulfonic acid,5-sulfosalicylic acid, and combinations thereof. In some embodiments,the acid is an inorganic acid selected from the group consisting ofnitric acid, sulfuric acid, hydrochloric acid, and combinations thereof.

In some embodiments, suitable bases for the photoresist developercomposition 57 include an alkanolamine, a triazole, or an ammoniumcompound. In some embodiments, suitable bases include an organic baseselected from the group consisting of monoethanolamine,monoisopropanolamine, 2-amino-2-methyl-1-propanol, 1H-benzotriazole,1,2,4-triazole, 1,8-diazabicycloundec-7-ene, tetramethylammoniumhydroxide, tetraethylammonium hydroxide, tetrapropylammonium hydroxide,and tetrabutylammonium hydroxide, and combinations thereof; or inorganicbases selected from the group consisting of ammonium hydroxide, ammoniumsulfamate, ammonium carbamate, and combinations thereof. In someembodiments, the base is selected from the group consisting ofmonoisopropanolamine, 2-amino-2-methyl-1-propanol, 1H-benzotriazole,1,2,4-triazole, 1,8-diazabicycloundec-7-ene, and combinations thereof.In some embodiments, the second solvent having a dielectric constantgreater than 18 includes water, methanol, ethanol, n-propanol,n-butanol, formic acid, formamide, acetone, methyl ethyl ketone,acetonitrile, dimethyl formamide, and dimethyl sulfoxide, or the like.In some embodiment, the concentration of the second solvent is fromabout 1 wt. % to about 40 wt. % based on the total weight of thedeveloper. In some embodiments, the second solvent is deionized water.

In some embodiments, the developer is mixture of propylene glycol methylether, deionized water, and formic acid. In other embodiments, thedeveloper is a mixture of propylene glycol methyl ether, deionizedwater, and acetic acid. And in other embodiments, the developer is amixture of propylene glycol methyl ether acetate, deionized water, andformic acid.

In some embodiments, the photoresist developer includes a chelate. Insome embodiments, the chelate is selected from the group consisting ofethylenediaminetetraacetic acid (EDTA), ethylenediamine-N,N′-disuccinicacid (EDDS), diethylenetriaminepentaacetic acid (DTPA), polyasparticacid, trans-1,2-cyclohexanediamine-N,N,N′,N′-tetraacetic acidmonohydrate, ethylenediamine, and combinations thereof, or the like. Insome embodiments, the chelate concentration is from about 0.001 wt. % toabout 20 wt. % of the total weight of the photoresist developer.

In some embodiments, the photoresist developer composition 57 includeshydrogen peroxide in a concentration of up to about 10 wt. % based onthe total weight of the developer.

In some embodiments, the photoresist developer composition 57 includesup to about 1 wt. % of a surfactant to increase the solubility andreduce the surface tension on the substrate. In some embodiments, thephotoresist developer surfactant is selected from the group consistingof alkylbenzenesulfonates, lignin sulfonates, fatty alcohol ethoxylates,and alkylphenol ethoxylates. In some embodiments, the surfactant isselected from the group consisting of sodium stearate, 4-(5-dodecyl)benzenesulfonate, ammonium lauryl sulfate, sodium lauryl sulfate, sodiumlaureth sulfate, sodium myreth sulfate, dioctyl sodium sulfosuccinate,perfluorooctanesulfonate, perfluorobutanesulfonate, alkyl-aryl etherphosphate, alkyl ether phosphates, sodium lauroyl sarcosinate,perfluoronononanoate, perfluorooctanoate, octenidine dihydrochloride,cetrimonium bromide, cetylpyridinium chloride, benzalkonium chloride,benzethonium chloride, dimethyldioctadecylammonium chloride,dioctadecyldimethylammonium bromide,3-[(3-cholamidopropyl)dimethylammonio]-1-propanesulfonate,cocamidopropyl hydroxysultaine, cocamidopropyl betaine,phospholipidsphosphatidylserine, phosphatidylethanolamine,phosphatidylcholine, sphingomyelins, octaethylene glycol monodecylether, pentaethylene glycol monodecyl ether, polyethoxylated tallowamine, cocamide monoethanolamine, cocamide diethanolamine, glycerolmonostearate, glycerol monolaurate, sorbitan monolaurate, sorbitanmonostearate, sorbitan tristearate, and combinations thereof.

In some embodiments, the developer 57 is applied to the photoresistlayer 15 using a spin-on process. In the spin-on process, the developer57 is applied to the photoresist layer 15 from above the photoresistlayer 15 while the photoresist coated substrate is rotated, as shown inFIG. 4 . In some embodiments, the developer 57 is supplied at a rate ofbetween about 5 ml/min and about 800 ml/min, while the photoresistcoated substrate 10 is rotated at a speed of between about 100 rpm andabout 2000 rpm. In some embodiments, the developer is at a temperatureof between about 10° C. and about 80° C. during the developmentoperation. The development operation continues for between about 10seconds to about 10 minutes in some embodiments.

While the spin-on operation is one suitable method for developing thephotoresist layer 15 after exposure, it is intended to be illustrativeand is not intended to limit the embodiment. Rather, any suitabledevelopment operations, including dip processes, puddle processes, andspray-on methods, may alternatively be used. All such developmentoperations are included within the scope of the embodiments.

During the development process, the developer composition 57 dissolvesthe photoresist regions 50 not exposed to radiation (i.e.—notcrosslinked), exposing the surface of the substrate 10, as shown in FIG.5 , and leaving behind well-defined exposed photoresist regions 52,having improved definition than provided by conventional negative tonephotoresist photolithography.

After the developing operation S150, remaining developer is removed fromthe patterned photoresist covered substrate. The remaining developer isremoved using a spin-dry process in some embodiments, although anysuitable removal technique may be used. After the photoresist layer 15is developed, and the remaining developer is removed, additionalprocessing is performed while the patterned photoresist layer 52 is inplace. For example, an etching operation, using dry or wet etching, isperformed in some embodiments, to transfer the pattern of thephotoresist layer 52 to the underlying substrate 10, forming recesses55′ as shown in FIG. 6 . The substrate 10 has a different etchresistance than the photoresist layer 15. In some embodiments, theetchant is more selective to the substrate 10 than the photoresist layer15.

In some embodiments, the substrate 10 and the photoresist layer 15contain at least one etching resistance molecule. In some embodiments,the etching resistant molecule includes a molecule having a low Onishinumber structure, a double bond, a triple bond, silicon, siliconnitride, titanium, titanium nitride, aluminum, aluminum oxide, siliconoxynitride, combinations thereof, or the like.

In some embodiments, a layer to be patterned 60 is disposed over thesubstrate prior to forming the photoresist layer, as shown in FIG. 7 .In some embodiments, the layer to be patterned 60 is a metallizationlayer or a dielectric layer, such as a passivation layer, disposed overa metallization layer. In embodiments where the layer to be patterned 60is a metallization layer, the layer to be patterned 60 is formed of aconductive material using metallization processes, and metal depositiontechniques, including chemical vapor deposition, atomic layerdeposition, and physical vapor deposition (sputtering). Likewise, if thelayer to be patterned 60 is a dielectric layer, the layer to bepatterned 60 is formed by dielectric layer formation techniques,including thermal oxidation, chemical vapor deposition, atomic layerdeposition, and physical vapor deposition.

The photoresist layer 15 is subsequently selectively exposed to actinicradiation 45 to form exposed regions 52 and unexposed regions 50 in thephotoresist layer, as shown in FIG. 8 , and described herein in relationto FIG. 3 . As explained herein the photoresist is a negativephotoresist, wherein polymer crosslinking occurs in the exposed regions52 in some embodiments.

As shown in FIG. 9 , the unexposed photoresist regions 50 are developedby dispensing developer 57 from a dispenser 62 to form a pattern ofphotoresist openings 55, as shown in FIG. 10 . The development operationis similar to that explained with reference to FIGS. 4 and 5 , herein.

Then as shown in FIG. 11 , the pattern 55 in the photoresist layer 15 istransferred to the layer to be patterned 60 using an etching operationand the photoresist layer is removed, as explained with reference toFIG. 6 to form pattern 55′ in the layer to be patterned 60.

In some embodiments, the selective exposure of the photoresist layer 15to form unexposed regions 50 and exposed regions 52 is performed usingextreme ultraviolet lithography. In an extreme ultraviolet lithographyoperation a reflective photomask 65 is used to form the patternedexposure light, as shown in FIG. 12 . The reflective photomask 65includes a low thermal expansion glass substrate 70, on which areflective multilayer 75 of Si and Mo is formed. A capping layer 80 andabsorber layer 85 are formed on the reflective multilayer 75. A rearconductive layer 90 is formed on the back side of the low thermalexpansion substrate 70. In extreme ultraviolet lithography, extremeultraviolet radiation 95 is directed towards the reflective photomask 65at an incident angle of about 6°. A portion 97 of the extremeultraviolet radiation is reflected by the Si/Mo multilayer 75 towardsthe photoresist coated substrate 10, while the portion of the extremeultraviolet radiation incident upon the absorber 85 is absorbed by thephotomask. In some embodiments, additional optics, including mirrors arebetween the reflective photomask 65 and the photoresist coatedsubstrate.

Other embodiments include other operations before, during, or after theoperations described above. In some embodiments, the disclosed methodsinclude forming fin field effect transistor (FinFET) structures. In someembodiments, a plurality of active fins are formed on the semiconductorsubstrate. Such embodiments, further include etching the substratethrough the openings of a patterned hard mask to form trenches in thesubstrate; filling the trenches with a dielectric material; performing achemical mechanical polishing (CMP) process to form shallow trenchisolation (STI) features; and epitaxy growing or recessing the STIfeatures to form fin-like active regions. In some embodiments, one ormore gate electrodes are formed on the substrate. Some embodimentsinclude forming gate spacers, doped source/drain regions, contacts forgate/source/drain features, etc. In other embodiments, a target patternis formed as metal lines in a multilayer interconnection structure. Forexample, the metal lines may be formed in an inter-layer dielectric(ILD) layer of the substrate, which has been etched to form a pluralityof trenches. The trenches may be filled with a conductive material, suchas a metal; and the conductive material may be polished using a processsuch as chemical mechanical planarization (CMP) to expose the patternedILD layer, thereby forming the metal lines in the ILD layer. The aboveare non-limiting examples of devices/structures that can be made and/orimproved using the method described herein.

In some embodiments, active components such diodes, field-effecttransistors (FETs), metal-oxide semiconductor field effect transistors(MOSFET), complementary metal-oxide semiconductor (CMOS) transistors,bipolar transistors, high voltage transistors, high frequencytransistors, FinFETs, other three-dimensional (3D) FETs, metal-oxidesemiconductor field effect transistors (MOSFET), complementarymetal-oxide semiconductor (CMOS) transistors, bipolar transistors, highvoltage transistors, high frequency transistors, other memory cells, andcombinations thereof are formed, according to embodiments of thedisclosure.

The novel photoresist developer compositions and negative photoresistphotolithography techniques according to the present disclosure providehigher semiconductor device feature density with reduced defects in ahigher efficiency process than conventional developers and techniques.The novel photoresist developer compositions and negative photoresistphotolithography techniques according to the present disclosure provideimproved removal of residue and scum from the developed photoresistpattern. The high dielectric constant (>18) solvent assists thedissociation of the acid or base to accelerate the removal ofphotoresist residue and scum in some embodiments.

An embodiment of the disclosure is a method of forming a pattern in aphotoresist, including forming a photoresist layer over a substrate, andselectively exposing the photoresist layer to actinic radiation to forma latent pattern. The latent pattern is developed by applying adeveloper composition to the selectively exposed photoresist layer toform a pattern. The developer composition includes a first solventhaving Hansen solubility parameters of 15<δ_(d)<25, 10<δ_(p)<25, and6<δ_(h)<30; an acid having an acid dissociation constant, pKa, of−15<pKa<5, or a base having a pKa of 40>pKa>9.5; and a second solventhaving a dielectric constant greater than 18. The first solvent and thesecond solvent are different solvents. In an embodiment, a concentrationof the first solvent ranges from 60 wt. % to 99 wt. % based on a totalweight of the developer composition. In an embodiment, a concentrationof the acid or base ranges from 0.001 wt. % to 20 wt. % based on a totalweight of the developer composition. In an embodiment, a concentrationof the second solvent ranges from 1 wt. % to 40 wt. % based on a totalweight of the developer composition. In an embodiment, the first solventis at least one of hexane, benzene, dimethyl sulfoxide, acetone,ethylene glycol, methanol, ethanol, propanol, isopropanol, propanediol,4-methyl-2-pentanone, butyldiglycol, ethyl acetate, butyl acetate,propylene glycol methyl ether acetate, propylene glycol methyl ether,diethyl ether, isobutyl propionate, tetrahydrofuran, hydrogen peroxide,or water. In an embodiment, the second solvent is at least one ofmethanol, ethanol, n-propanol, n-butanol, formic acid, formamide,acetone, methyl ethyl ketone, acetonitrile, dimethyl formamide, dimethylsulfoxide, or water. In an embodiment, the developer compositionincludes the acid, and the acid is at least one of ethanedioic acid,methanoic acid, 2-hydroxypropanoic acid, 2-hydroxybutanedioic acid,citric acid, uric acid, trifluoromethanesulfonic acid, benzenesulfonicacid, ethanesulfonic acid, methanesulfonic acid, oxalic acid, maleicacid, carbonic acid, oxoethanoic acid, 2-hydroxyethanoic acid,propanedioic acid, butanedioic acid, 3-oxobutanoic acid,hydroxylamine-o-sulfonic acid, formamidinesulfinic acid, methylsulfamicacid, sulfoacetic acid, 1,1,2,2-tetrafluoroethanesulfonic acid,1,3-propanedisulfonic acid, nonafluorobutane-1-sulfonic acid,5-sulfosalicylic acid, nitric acid, sulfuric acid, or hydrochloric acid.In an embodiment, the base is at least one of an alkanolamine, atriazole, or an ammonium compound. In an embodiment, the developercomposition includes the base, and the base is at least one ofmonoethanolamine, monoisopropanolamine, 2-amino-2-methyl-1-propanol,1H-benzotriazole, 1,2,4-triazole, 1,8-diazabicycloundec-7-ene,tetramethylammonium hydroxide, tetraethylammonium hydroxide,tetrapropylammonium hydroxide, tetrabutylammonium hydroxide, ammoniumhydroxide, ammonium sulfamate, or ammonium carbamate. In an embodiment,the method includes heating the photoresist layer after selectivelyexposing the photoresist layer to actinic radiation and beforedeveloping the photoresist layer. In an embodiment, the developercomposition is at a temperature of about 25° C. to about 75° C. duringthe developing. In an embodiment, the method includes heating thephotoresist layer before selectively exposing the photoresist layer toactinic radiation. In an embodiment, the developer composition includesa surfactant. In an embodiment, a concentration of the surfactant isfrom 0.001 wt. % to 1 wt. % based on a total weight of the developercomposition.

Another embodiment of the disclosure is a method including forming aresist layer over a substrate. The resist layer is patternwisecrosslinked to form a latent pattern in the resist layer including acrosslinked portion and an uncrosslinked portion of the resist layer.The latent pattern is developed by applying a developer composition toremove the uncrosslinked portion of the resist layer to form a patternof the crosslinked portion of the resist layer. The developercomposition includes a first solvent having Hansen solubility parametersof 15<δ_(d)<25, 10<δ_(p)<25, and 6<δ_(h)<30; an acid having an aciddissociation constant, pKa, of −15<pKa<5, or a base having a pKa of40>pKa>9.5; and a second solvent having a dielectric constant greaterthan 18. The first solvent and second solvent are different solvents. Inan embodiment, the method includes heating the resist layer afterselectively exposing the resist layer to actinic radiation and beforedeveloping the resist layer. In an embodiment, the first solvent is atleast one of hexane, benzene, dimethyl sulfoxide, acetone, ethyleneglycol, methanol, ethanol, propanol, isopropanol, propanediol,4-methyl-2-pentanone, butyldiglycol, ethyl acetate, butyl acetate,propylene glycol methyl ether acetate, propylene glycol methyl ether,diethyl ether, isobutyl propionate, tetrahydrofuran, hydrogen peroxide,or water. In an embodiment, the second solvent is at least one ofmethanol, ethanol, n-propanol, n-butanol, formic acid, formamide,acetone, methyl ethyl ketone, acetonitrile, dimethyl formamide, dimethylsulfoxide, or water. In an embodiment, the developer compositionincludes the acid, and the acid is at least one of ethanedioic acid,methanoic acid, 2-hydroxypropanoic acid, 2-hydroxybutanedioic acid,citric acid, uric acid, trifluoromethanesulfonic acid, benzenesulfonicacid, ethanesulfonic acid, methanesulfonic acid, oxalic acid, maleicacid, carbonic acid, oxoethanoic acid, 2-hydroxyethanoic acid,propanedioic acid, butanedioic acid, 3-oxobutanoic acid,hydroxylamine-o-sulfonic acid, formamidinesulfinic acid, methylsulfamicacid, sulfoacetic acid, 1,1,2,2-tetrafluoroethanesulfonic acid,1,3-propanedisulfonic acid, nonafluorobutane-1-sulfonic acid,5-sulfosalicylic acid, nitric acid, sulfuric acid, or hydrochloric acid.In an embodiment, the developer composition includes the base, and thebase is at least one of monoethanolamine, monoisopropanolamine,2-amino-2-methyl-1-propanol, 1H-benzotriazole, 1,2,4-triazole,1,8-diazabicycloundec-7-ene, tetramethylammonium hydroxide,tetraethylammonium hydroxide, tetrapropylammonium hydroxide,tetrabutylammonium hydroxide, ammonium hydroxide, ammonium sulfamate, orammonium carbamate. In an embodiment, a concentration of the firstsolvent ranges from 60 wt. % to 99 wt. % based on a total weight of thedeveloper composition. In an embodiment, a concentration of the acid orbase ranges from 0.001 wt. % to 20 wt. % based on a total weight of thedeveloper composition. In an embodiment, a concentration of the secondsolvent ranges from 1 wt. % to 40 wt. % based on a total weight of thedeveloper composition. In an embodiment, the developer composition is ata temperature of about 25° C. to about 75° C. during the developing. Inan embodiment, the method includes heating the resist layer beforepatternwise crosslinking the resist layer. In an embodiment, thedeveloper composition includes from 0.001 wt. % to 1 wt. % of asurfactant based on a total weight of the developer composition.

Another embodiment of the disclosure is a photoresist developercomposition, including a first solvent having Hansen solubilityparameters of 15<δ_(a)<25, 10<δ_(p)<25, and 6<δ_(h)<30; an acid havingan acid dissociation constant, pKa, of −15<pKa<5, or a base having a pKaof 40>pKa>9.5; and a second solvent having a dielectric constant greaterthan 18. The first solvent and the second solvent are differentsolvents. In an embodiment, the first solvent is at least one of hexane,benzene, dimethyl sulfoxide, acetone, ethylene glycol, methanol,ethanol, propanol, isopropanol, propanediol, 4-methyl-2-pentanone,butyldiglycol, ethyl acetate, butyl acetate, propylene glycol methylether acetate, propylene glycol methyl ether, diethyl ether, isobutylpropionate, tetrahydrofuran, hydrogen peroxide, or water. In anembodiment, the second solvent is at least one of methanol, ethanol,n-propanol, n-butanol, formic acid, formamide, acetone, methyl ethylketone, acetonitrile, dimethyl formamide, dimethyl sulfoxide, or water.In an embodiment, the developer composition includes the acid, and theacid is at least one of ethanedioic acid, methanoic acid,2-hydroxypropanoic acid, 2-hydroxybutanedioic acid, citric acid, uricacid, trifluoromethanesulfonic acid, benzenesulfonic acid,ethanesulfonic acid, methanesulfonic acid, oxalic acid, maleic acid,carbonic acid, oxoethanoic acid, 2-hydroxyethanoic acid, propanedioicacid, butanedioic acid, 3-oxobutanoic acid, hydroxylamine-o-sulfonicacid, formamidinesulfinic acid, methylsulfamic acid, sulfoacetic acid,1,1,2,2-tetrafluoroethanesulfonic acid, 1,3-propanedisulfonic acid,nonafluorobutane-1-sulfonic acid, 5-sulfosalicylic acid, nitric acid,sulfuric acid, or hydrochloric acid. In an embodiment, the developercomposition includes the base, and the base is at least one ofmonoethanolamine, monoisopropanolamine, 2-amino-2-methyl-1-propanol,1H-benzotriazole, 1,2,4-triazole, 1,8-diazabicycloundec-7-ene,tetramethylammonium hydroxide, tetraethylammonium hydroxide,tetrapropylammonium hydroxide, tetrabutylammonium hydroxide, ammoniumhydroxide, ammonium sulfamate, or ammonium carbamate. In an embodiment,a concentration of the first solvent is from 60 wt. % to 99 wt. % basedon a total weight of the photoresist developer composition. In anembodiment, a concentration of the acid or base is from 0.001 wt. % to20 wt. % based on a total weight of the photoresist developercomposition. In an embodiment, a concentration of the second solvent isfrom 1 wt. % to 40 wt. % based on a total weight of the photoresistdeveloper composition. In an embodiment, the photoresist developercomposition includes a surfactant. In an embodiment, a concentration ofthe surfactant is from 0.001 wt. % to 1 wt. % based on a total weight ofthe photoresist developer composition.

Another embodiment of the disclosure is a method of patterning aphotoresist layer including forming a negative tone photoresist layerover a substrate. The photoresist layer is selectively exposed toactinic radiation to form a latent pattern. Portions of the photoresistlayer not exposed to the actinic radiation are removed by applying adeveloper composition to the selectively exposed photoresist layer toform a pattern. The developer composition includes a first solvent, asecond solvent, and an organic acid or an organic base. The firstsolvent is at least one of hexane, benzene, dimethyl sulfoxide, acetone,ethylene glycol, methanol, ethanol, propanol, isopropanol, propanediol,4-methyl-2-pentanone, butyldiglycol, ethyl acetate, butyl acetate,propylene glycol methyl ether acetate, propylene glycol methyl ether,diethyl ether, isobutyl propionate, tetrahydrofuran, hydrogen peroxide,or water. The organic acid is at least one of ethanedioic acid,methanoic acid, 2-hydroxypropanoic acid, 2-hydroxybutanedioic acid,citric acid, uric acid, trifluoromethanesulfonic acid, benzenesulfonicacid, ethanesulfonic acid, methanesulfonic acid, oxalic acid, maleicacid, carbonic acid, oxoethanoic acid, 2-hydroxyethanoic acid,propanedioic acid, butanedioic acid, 3-oxobutanoic acid,hydroxylamine-o-sulfonic acid, formamidinesulfinic acid, methylsulfamicacid, sulfoacetic acid, 1,1,2,2-tetrafluoroethanesulfonic acid,1,3-propanedisulfonic acid, nonafluorobutane-1-sulfonic acid, or5-sulfosalicylic acid. The organic base is at least one ofmonoethanolamine, monoisopropanolamine, 2-amino-2-methyl-1-propanol,1H-benzotriazole, 1,2,4-triazole, 1,8-diazabicycloundec-7-ene,tetramethylammonium hydroxide, tetraethylammonium hydroxide,tetrapropylammonium hydroxide, tetrabutylammonium hydroxide. The secondsolvent is at least one of methanol, ethanol, n-propanol, n-butanol,formic acid, formamide, acetone, methyl ethyl ketone, acetonitrile,dimethyl formamide, dimethyl sulfoxide, or water. The first solvent andsecond solvent are different solvents. In an embodiment, a concentrationof the first solvent ranges from 60 wt. % to 99 wt. % based on a totalweight of the developer composition. In an embodiment, a concentrationof the acid or base ranges from 0.001 wt. % to 20 wt. % based on a totalweight of the developer composition. In an embodiment, a concentrationof the second solvent ranges from 1 wt. % to 40 wt. % based on a totalweight of the developer composition. In an embodiment, the methodincludes heating the photoresist layer after selectively exposing thephotoresist layer to actinic radiation and before removing portions ofthe photoresist layer. In an embodiment, the developer compositionincludes a surfactant. In an embodiment, a concentration of thesurfactant is from 0.001 wt. % to 1 wt. % based on a total weight of thedeveloper composition. In an embodiment, the developer composition is ata temperature of about 25° C. to about 75° C. during the developing. Inan embodiment, the method includes heating the photoresist layer beforeselectively exposing the photoresist layer to actinic radiation.

Another embodiment of the disclosure is a photoresist developercomposition including a first solvent, a second solvent, and an organicacid or an organic base. The first solvent is at least one of hexane,benzene, dimethyl sulfoxide, acetone, ethylene glycol, methanol,ethanol, propanol, isopropanol, propanediol, 4-methyl-2-pentanone,butyldiglycol, ethyl acetate, butyl acetate, propylene glycol methylether acetate, propylene glycol methyl ether, diethyl ether, isobutylpropionate, tetrahydrofuran, hydrogen peroxide, or water. The organicacid is at least one of ethanedioic acid, methanoic acid,2-hydroxypropanoic acid, 2-hydroxybutanedioic acid, citric acid, uricacid, trifluoromethanesulfonic acid, benzenesulfonic acid,ethanesulfonic acid, methanesulfonic acid, oxalic acid, maleic acid,carbonic acid, oxoethanoic acid, 2-hydroxyethanoic acid, propanedioicacid, butanedioic acid, 3-oxobutanoic acid, hydroxylamine-o-sulfonicacid, formamidinesulfinic acid, methylsulfamic acid, sulfoacetic acid,1,1,2,2-tetrafluoroethanesulfonic acid, 1,3-propanedisulfonic acid,nonafluorobutane-1-sulfonic acid, or 5-sulfosalicylic acid. The organicbase is at least one of monoethanolamine, monoisopropanolamine,2-amino-2-methyl-1-propanol, 1H-benzotriazole, 1,2,4-triazole,1,8-diazabicycloundec-7-ene, tetramethylammonium hydroxide,tetraethylammonium hydroxide, tetrapropylammonium hydroxide,tetrabutylammonium hydroxide. The second solvent is at least is at leastone of methanol, ethanol, n-propanol, n-butanol, formic acid, formamide,acetone, methyl ethyl ketone, acetonitrile, dimethyl formamide, dimethylsulfoxide, or water. The first solvent and second solvent are differentsolvents. In an embodiment, a concentration of the first solvent rangesfrom 60 wt. % to 99 wt. % based on a total weight of the developercomposition. In an embodiment, a concentration of the acid or baseranges from 0.001 wt. % to 20 wt. % based on a total weight of thedeveloper composition. In an embodiment, a concentration of the secondsolvent ranges from 1 wt. % to 40 wt. % based on a total weight of thedeveloper composition. In an embodiment, the developer compositionincludes a surfactant. In an embodiment, the surfactant is at least oneof alkylbenzenesulfonates, lignin sulfonates, fatty alcohol ethoxylates,or alkylphenol ethoxylates. In an embodiment, the surfactant is at leastone of sodium stearate, 4-(5-dodecyl) benzenesulfonate, ammonium laurylsulfate, sodium lauryl sulfate, sodium laureth sulfate, sodium myrethsulfate, dioctyl sodium sulfosuccinate, perfluorooctanesulfonate,perfluorobutanesulfonate, alkyl-aryl ether phosphate, alkyl etherphosphates, sodium lauroyl sarcosinate, perfluoronononanoate,perfluorooctanoate, octenidine dihydrochloride, cetrimonium bromide,cetylpyridinium chloride, benzalkonium chloride, benzethonium chloride,dimethyldioctadecylammonium chloride, dioctadecyldimethylammoniumbromide, 3-[(3-cholamidopropyl)dimethylammonio]-1-propanesulfonate,cocamidopropyl hydroxysultaine, cocamidopropyl betaine,phospholipidsphosphatidylserine, phosphatidylethanolamine,phosphatidylcholine, sphingomyelins, octaethylene glycol monodecylether, pentaethylene glycol monodecyl ether, polyethoxylated tallowamine, cocamide monoethanolamine, cocamide diethanolamine, glycerolmonostearate, glycerol monolaurate, sorbitan monolaurate, sorbitanmonostearate, or sorbitan tristearate. In an embodiment, a concentrationof the surfactant is from 0.001 wt. % to 1 wt. % based on a total weightof the developer composition.

Another embodiment of the disclosure is a photoresist developercomposition including a first solvent, a second solvent, and aninorganic acid or an inorganic base. The first solvent is at least oneof hexane, benzene, dimethyl sulfoxide, acetone, ethylene glycol,methanol, ethanol, propanol, isopropanol, propanediol,4-methyl-2-pentanone, butyldiglycol, ethyl acetate, butyl acetate,propylene glycol methyl ether acetate, propylene glycol methyl ether,diethyl ether, isobutyl propionate, tetrahydrofuran, hydrogen peroxide,or water. The inorganic acid is at least one of nitric acid, sulfuricacid, or hydrochloric acid. The inorganic base is at least one ofammonium hydroxide, ammonium sulfamate, or ammonium carbamate. Thesecond solvent is at least one of methanol, ethanol, n-propanol,n-butanol, formic acid, formamide, acetone, methyl ethyl ketone,acetonitrile, dimethyl formamide, dimethyl sulfoxide, or water. Thefirst solvent and second solvent are different solvents. In anembodiment, a concentration of the first solvent ranges from 60 wt. % to99 wt. % based on a total weight of the developer composition. In anembodiment, a concentration of the acid or base ranges from 0.001 wt. %to 20 wt. % based on a total weight of the developer composition. In anembodiment, a concentration of the second solvent ranges from 1 wt. % to40 wt. % based on a total weight of the developer composition. In anembodiment, the developer composition includes a surfactant. In anembodiment, the surfactant is at least one of alkylbenzenesulfonates,lignin sulfonates, fatty alcohol ethoxylates, or alkylphenolethoxylates. In an embodiment, the surfactant is at least one of sodiumstearate, 4-(5-dodecyl) benzenesulfonate, ammonium lauryl sulfate,sodium lauryl sulfate, sodium laureth sulfate, sodium myreth sulfate,dioctyl sodium sulfosuccinate, perfluorooctanesulfonate,perfluorobutanesulfonate, alkyl-aryl ether phosphate, alkyl etherphosphates, sodium lauroyl sarcosinate, perfluoronononanoate,perfluorooctanoate, octenidine dihydrochloride, cetrimonium bromide,cetylpyridinium chloride, benzalkonium chloride, benzethonium chloride,dimethyldioctadecylammonium chloride, dioctadecyldimethylammoniumbromide, 3-[(3-cholamidopropyl)dimethylammonio]-1-propanesulfonate,cocamidopropyl hydroxysultaine, cocamidopropyl betaine,phospholipidsphosphatidylserine, phosphatidylethanolamine,phosphatidylcholine, sphingomyelins, octaethylene glycol monodecylether, pentaethylene glycol monodecyl ether, polyethoxylated tallowamine, cocamide monoethanolamine, cocamide diethanolamine, glycerolmonostearate, glycerol monolaurate, sorbitan monolaurate, sorbitanmonostearate, or sorbitan tristearate. In an embodiment, a concentrationof the surfactant is from 0.001 wt. % to 1 wt. % based on a total weightof the developer.

The foregoing outlines features of several embodiments or examples sothat those skilled in the art may better understand the aspects of thepresent disclosure. Those skilled in the art should appreciate that theymay readily use the present disclosure as a basis for designing ormodifying other processes and structures for carrying out the samepurposes and/or achieving the same advantages of the embodiments orexamples introduced herein. Those skilled in the art should also realizethat such equivalent constructions do not depart from the spirit andscope of the present disclosure, and that they may make various changes,substitutions, and alterations herein without departing from the spiritand scope of the present disclosure.

What is claimed is:
 1. A method of forming a pattern in a photoresist,comprising: forming a photoresist layer over a substrate; selectivelyexposing the photoresist layer to actinic radiation to form a latentpattern; and developing the latent pattern by applying a developercomposition to the selectively exposed photoresist layer to form apattern, wherein the developer composition comprises: a first solventhaving Hansen solubility parameters of 15<δ_(d)<25, 10<δ_(p)<25, and6<δ_(h)<30; an acid having an acid dissociation constant, pKa, of−15<pKa<5, or a base having a pKa of 40>pKa>9.5; and a second solventhaving a dielectric constant greater than 18, and wherein the firstsolvent and the second solvent are different solvents.
 2. The methodaccording to claim 1, wherein a concentration of the first solventranges from 60 wt. % to 99 wt. % based on a total weight of thedeveloper composition.
 3. The method according to claim 1, wherein aconcentration of the acid or base ranges from 0.001 wt. % to 20 wt. %based on a total weight of the developer composition.
 4. The methodaccording to claim 1, wherein a concentration of the second solventranges from 1 wt. % to 40 wt. % based on a total weight of the developercomposition.
 5. The method according to claim 1, wherein the firstsolvent is at least one of hexane, benzene, dimethyl sulfoxide, acetone,ethylene glycol, methanol, ethanol, propanol, isopropanol, propanediol,4-methyl-2-pentanone, butyldiglycol, ethyl acetate, butyl acetate,propylene glycol methyl ether acetate, propylene glycol methyl ether,diethyl ether, isobutyl propionate, tetrahydrofuran, hydrogen peroxide,or water.
 6. The method according to claim 1, wherein the second solventis at least one of methanol, ethanol, n-propanol, n-butanol, formicacid, formamide, acetone, methyl ethyl ketone, acetonitrile, dimethylformamide, dimethyl sulfoxide, or water.
 7. The method according toclaim 1, wherein: the developer composition includes the acid, and theacid is at least one of ethanedioic acid, formic acid, acetic acid,propanoic acid, 2-hydroxypropanoic acid, butanoic acid,2-hydroxybutanedioic acid, pentanoic acid, hexanoic acid, heptanoicacid, caprylic acid, citric acid, uric acid, trifluoromethanesulfonicacid, benzenesulfonic acid, ethanesulfonic acid, methanesulfonic acid,oxalic acid, maleic acid, carbonic acid, oxoethanoic acid,2-hydroxyethanoic acid, propanedioic acid, butanedioic acid,3-oxobutanoic acid, hydroxylamine-o-sulfonic acid, formamidinesulfinicacid, methylsulfamic acid, sulfoacetic acid,1,1,2,2-tetrafluoroethanesulfonic acid, 1,3-propanedisulfonic acid,nonafluorobutane-1-sulfonic acid, 5-sulfosalicylic acid, nitric acid,sulfuric acid, or hydrochloric acid.
 8. The method according to claim 1,wherein: the developer composition comprises the base, and the base isat least one of an alkanolamine, a triazole, or an ammonium compound. 9.The method according to claim 1, wherein the base is at least one ofmonoethanolamine, monoisopropanolamine, 2-amino-2-methyl-1-propanol,1H-benzotriazole, 1,2,4-triazole, 1,8-diazabicycloundec-7-ene,tetramethylammonium hydroxide, tetraethylammonium hydroxide,tetrapropylammonium hydroxide, tetrabutylammonium hydroxide, ammoniumhydroxide, ammonium sulfamate, or ammonium carbamate.
 10. A method,comprising: forming a resist layer over a substrate; patternwisecrosslinking the resist layer to form a latent pattern in the resistlayer including a crosslinked portion and an uncrosslinked portion ofthe resist layer; and developing the latent pattern by applying adeveloper composition to remove the uncrosslinked portion of the resistlayer to form a pattern of the crosslinked portion of the resist layer,wherein the developer composition comprises: a first solvent havingHansen solubility parameters of 15<δ_(d)<25, 10<δ_(p)<25, and6<δ_(h)<30; an acid having an acid dissociation constant, pKa, of−15<pKa<5, or a base having a pKa of 40>pKa>9.5; and a second solventhaving a dielectric constant greater than 18, and wherein the firstsolvent and second solvent are different solvents.
 11. The methodaccording to claim 10, further comprising heating the resist layer afterselectively exposing the resist layer to actinic radiation and beforedeveloping the resist layer.
 12. The method according to claim 10,wherein the first solvent is at least one of hexane, benzene, dimethylsulfoxide, acetone, ethylene glycol, methanol, ethanol, propanol,isopropanol, propanediol, 4-methyl-2-pentanone, butyldiglycol, ethylacetate, butyl acetate, propylene glycol methyl ether acetate, propyleneglycol methyl ether, diethyl ether, isobutyl propionate,tetrahydrofuran, hydrogen peroxide, or water.
 13. The method accordingto claim 10, wherein the second solvent is at least one of methanol,ethanol, n-propanol, n-butanol, formic acid, formamide, acetone, methylethyl ketone, acetonitrile, dimethyl formamide, dimethyl sulfoxide, orwater.
 14. The method according to claim 10, wherein: the developercomposition includes the acid, and the acid is at least one ofethanedioic acid, formic acid, acetic acid, propanoic acid,2-hydroxypropanoic acid, butanoic acid, 2-hydroxybutanedioic acid,pentanoic acid, hexanoic acid, heptanoic acid, caprylic acid, citricacid, uric acid, trifluoromethanesulfonic acid, benzenesulfonic acid,ethanesulfonic acid, methanesulfonic acid, oxalic acid, maleic acid,carbonic acid, oxoethanoic acid, 2-hydroxyethanoic acid, propanedioicacid, butanedioic acid, 3-oxobutanoic acid, hydroxylamine-o-sulfonicacid, formamidinesulfinic acid, methylsulfamic acid, sulfoacetic acid,1,1,2,2-tetrafluoroethanesulfonic acid, 1,3-propanedisulfonic acid,nonafluorobutane-1-sulfonic acid, 5-sulfosalicylic acid, nitric acid,sulfuric acid, or hydrochloric acid.
 15. The method according to claim10, wherein: the developer composition includes the base, and the baseis at least one of monoethanolamine, monoisopropanolamine,2-amino-2-methyl-1-propanol, 1H-benzotriazole, 1,2,4-triazole,1,8-diazabicycloundec-7-ene, tetramethylammonium hydroxide,tetraethylammonium hydroxide, tetrapropylammonium hydroxide,tetrabutylammonium hydroxide, ammonium hydroxide, ammonium sulfamate, orammonium carbamate.
 16. A photoresist developer composition, comprising:a first solvent having Hansen solubility parameters of 15<δ_(d)<25,10<δ_(p)<25, and 6<δ_(h)<30; an acid having an acid dissociationconstant, pKa, of −15<pKa<5, or a base having a pKa of 40>pKa>9.5; and asecond solvent having a dielectric constant greater than 18, wherein thefirst solvent and the second solvent are different solvents.
 17. Thephotoresist developer composition of claim 16, wherein the first solventis at least one of hexane, benzene, dimethyl sulfoxide, acetone,ethylene glycol, methanol, ethanol, propanol, isopropanol, propanediol,4-methyl-2-pentanone, butyldiglycol, ethyl acetate, butyl acetate,propylene glycol methyl ether acetate, propylene glycol methyl ether,diethyl ether, isobutyl propionate, tetrahydrofuran, hydrogen peroxide,or water.
 18. The photoresist developer composition of claim 16, whereinthe second solvent is at least one of methanol, ethanol, n-propanol,n-butanol, formic acid, formamide, acetone, methyl ethyl ketone,acetonitrile, dimethyl formamide, dimethyl sulfoxide, or water.
 19. Thephotoresist developer composition of claim 16, wherein: the developercomposition includes the acid, and the acid is at least one ofethanedioic acid, formic acid, acetic acid, propanoic acid,2-hydroxypropanoic acid, butanoic acid, 2-hydroxybutanedioic acid,pentanoic acid, hexanoic acid, heptanoic acid, caprylic acid, citricacid, uric acid, trifluoromethanesulfonic acid, benzenesulfonic acid,ethanesulfonic acid, methanesulfonic acid, oxalic acid, maleic acid,carbonic acid, oxoethanoic acid, 2-hydroxyethanoic acid, propanedioicacid, butanedioic acid, 3-oxobutanoic acid, hydroxylamine-o-sulfonicacid, formamidinesulfinic acid, methylsulfamic acid, sulfoacetic acid,1,1,2,2-tetrafluoroethanesulfonic acid, 1,3-propanedisulfonic acid,nonafluorobutane-1-sulfonic acid, 5-sulfosalicylic acid, nitric acid,sulfuric acid, or hydrochloric acid.
 20. The photoresist developercomposition of claim 16, wherein: the developer composition includes thebase, and the base is at least one of monoethanolamine,monoisopropanolamine, 2-amino-2-methyl-1-propanol, 1H-benzotriazole,1,2,4-triazole, 1,8-diazabicycloundec-7-ene, tetramethylammoniumhydroxide, tetraethylammonium hydroxide, tetrapropylammonium hydroxide,tetrabutylammonium hydroxide, ammonium hydroxide, ammonium sulfamate, orammonium carbamate.